​Is It Bad to Eat Dairy If It Gives You Diarrhea?

If eating a cup of ice cream or drinking a glass of milk sends you scurrying to the bathroom or starts your gut gurgling, you might have lactose intolerance.

And you’re not alone. About 65 percent of the world’s population has some issues digesting milk products. And the effects don’t need to be as severe as full-blown diarrhea—even symptoms like slight bloating or mild cramping can indicate a problem.

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But the question is, what’s your move if you do have a sensitivity to things like milk, cheese, and ice cream? Are you destined to a life sans dairy? And if you choose to eat the good stuff anyway—symptoms be damned—are you putting your body at risk? We break it down below. (Plus, find out if dairy really causes acne, here.)

What Exactly Is Lactose Intolerance?

When you eat foods containing lactose—a sugar found in milk products—an enzyme called lactase works to break down the sugar into smaller particles, explains Jennifer Inra, M.D., a gastroenterologist at Brigham and Women’s Hospital in Boston, MA.

These smaller particles are easier for your GI tract to absorb and digest. A problem arises, though, if your body doesn’t produce enough lactase to break the milk sugars down.

And that’s a common side effect of growing older, says Dana Hunnes, R.D., a senior dietitian at Ronald Reagan UCLA Medical Center.

“As infants, we require milk [preferably breastmilk or a similar alternative] to properly access healthful nutrition,” she says.

But after that, we can get our nutrients form solid food, so we no longer need to drink milk. As a result, many of lose the lactase enzyme that allows us to break those milk sugars down into smaller parts, says Hunnes.

That’s what causes lactose intolerance. Without enough of the lactase enzyme, your body can’t metabolize dairy, leading to digestive problems like diarrhea, abdominal cramping or pain, bloating, gas, nausea, and sometimes even vomiting about 30 minutes to two hours after eating it. (Here’s what to do if you get diarrhea on a run.)

“The severity of symptoms typically increases with the amount of lactose you eat,” says Dr. Inra.

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Usually, lactose intolerance is something that develops as you age—you’ll usually notice some symptoms start to begin in adolescence.

It’s also possible to pick up symptoms later in life, says Dr. Inra. An injury to your small intestine—from infection or inflammation, such as from celiac disease or inflammatory bowel disorders—can also lead to lactose intolerance. The good news, though, is in these cases, your lactase levels will return to normal after you treat the underlying disease.

Otherwise, lactose intolerance doesn’t get better over time—even if you try to reintroduce yourself to dairy little by little, she says.

So How Bad Is It to Eat Dairy If You’re Lactose Intolerant?

Lactose intolerance isn’t dangerous, Dr. Inra notes, and if you splurge on the cheesy nachos, there will likely be no long-term consequences.

But, that’s not the case 100 percent of the time: “There are some individuals who actually do have permanent damage done to the microvilli [finger projections lining the intestine] of their intestine when they drink or consume foods with lactose in it,” says Hunnes.

And that’s a problem, since the microvilli absorb nutrients into your bloodstream. So if they are damaged, you won’t be able to absorb and utilize your nutrients properly. The result? Malnutrition, says Hunnes, which can leave you lacking the nutrients you need.

But don’t freak out—it’s a very rare condition, affecting less than one percent of the population, she says.

Most of us, instead, pay for eating dairy with the nasty—albeit temporary—symptoms listed above. In most cases, you’ll start to feel better once everything is through your system, about 12 to 24 hours later, says Hunnes. (Here are 12 reasons your stomach hurts.)

Still, even if you’re lactose intolerant, you don’t have to swear off cheese. You just need a better game plan, and that can include some OTC meds that can help you digest dairy.

“Lactaid pills and other similar products such as Dairy-Ease contain the enzyme lactase, and help some people tolerate dairy,” says Dr. Inra.

Just make sure to take the pills before eating dairy. “If they are taken later, they may not work as well.”

One important note: The OTC pills aren’t foolproof, either. Many people have mild symptoms even with a lactase enzyme supplement, because these meds may not be able to break down all the lactose present in your food—say, especially if you’re eating foods with lots of lactose, says Dr. Inra.

“Younger, fresher cheeses, such as American, feta, and mozzarella have higher lactose content,” she says.

Plus, fermented foods such as yogurt and kefir are also naturally lower in lactose, too, says Hunnes. On the other hand, reduced-fat and fat-free dairy products also tend to have a higher lactose contents, Dr. Inra says.

Fortunately, we also live in an age of dairy-free and lactose-free foods and drinks. “Almond milk, soy milk, or Lactaid milk are good options instead of regular milk,” says Dr. Inra.

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